With this example we are going to demonstrate how to compare Date objects with compareTo method of the Date class. In short, to compare a Date object with another you should:
- Create a new Date object, using the
Date()constructor, that allocates a Date object and initializes it so that it represents the time at which it was allocated, measured to the nearest millisecond. - Create a new Calendar, using
getInstance()API method of Calendar, that gets a calendar using the default time zone and locale. - Use
set(int field, int value)API method of Calendar to set a future value, e.g. year to the calendar object. - Use
getTime()API method of Calendar. The method returns a Date object representing this Calendar’s time value, with millisecond offset from the January 1 1970 00:00:00.000 GMT. - Invoke
compareTo(Date anotherDate)API method of Date, using the two Date objects. The method compares the two Dates for ordering and returns an int value, that is 0 if the argument Date is equal to the Date tat calls the method, a value less than 0 if this Date is before the Date argument; and a value greater than 0 if this Date is after the Date argument.
Let’s take a look at the code snippet that follows:
package com.javacodegeeks.snippets.core;
import java.util.Calendar;
import java.util.Date;
public class CompareDateObjectsWithCompareToMethod {
public static void main(String[] args) {
Date now = new Date();
Calendar c = Calendar.getInstance();
c.set(Calendar.YEAR, 2100);
Date future = c.getTime();
int d = now.compareTo(future);
if (d<0) {
System.out.println(now + " is before " + future);
}
else if (d>0) {
System.out.println(now + " is after " + future);
}
else {
System.out.println("Dates are equal");
}
}
}
Output:
Thu Oct 20 16:19:55 EEST 2011 is before Wed Oct 20 16:19:55 EEST 2100
This was an example of how to compare Date objects with compareTo(Date anotherDate) method of Date in Java.
